k_thread_stack_free() is designed to be called with any pointer
value. We return -EINVAL when an attempt is made to free an
invalid stack pointer.
This change reduces the verbosity in the degenerate case, when
the pointer is not obtained via k_thread_stack_alloc(), but
otherwise does not affect functionality.
If debug log verbosity is not enabled, we save a few bytes in
.text / .rodata / .strtab.
Signed-off-by: Christopher Friedt <cfriedt@meta.com>
9f3d7776ab